Convection cooking has slowly but surely found its place in mainstream kitchen cooking products. Convection cooking appliances use a combination of heaters and fans to circulate oven air, which is maintained at a user selected cooking temperature by a microcontroller or gas expansion thermostat, over the heater and the food being heated.
In standard non-convection bake and broil cooking, a thermal boundary layer is formed near the food product being heated. This boundary layer can reduce heat transfer to the food by a nominal 25%. The circulating fan in current art convection ovens serves to break up this boundary layer.
Furthermore, some of these convection systems are designed with a resistive heating element surrounding the fan impeller, creating what the appliance industry calls “true convection” cooking. This fan associated heating element is often used to increase the temperature of the circulating air, thereby supplying cabinet losses present in the oven cavity as well as energy required to heat the food. Current convection ovens provide little if any radiant heating of food product placed in the oven cavity.
Smoke and odor elimination in connection with current food heating appliances are typically handled by bleeding a small amount of range or oven cavity air into a single pass, low temperature catalytic element located between the range cavity and the appliance's exhaust plenum to oxidize airborne cooking products on their way to the kitchen air. These single pass systems cannot effectively handle the large quantities of smoke and odor created in high performance and high power bake and broil ovens, nor are they well suited for smoke and odor handling present in higher temperature (>500° F.) self-clean operations.
U.S. Pat. No. 6,318,245 B1 by Durth et al. and U.S. Pat. No. 4,113,439 by Ookubo et al. present cooking devices having catalysts. The present invention is a novel improvement over these and other devices.